mmime generates a
‘multipart/mixed’ message from the
standard input, extending, wrapping, and encoding the header as necessary, and
replacing lines in the message body of the form

#content/type[

#content-disposition

]
path[

>filename

]

with a MIME part having Content-Type
content/type, consisting of the contents of
the file found at path.
content-disposition is optional and defaults
to ‘attachment’. filename is
optional and defaults to the basename of
path.